Dental lighting system



Jan. 8, 1935. H. L. LOGAN 1,987,019

I DENTAL LIGHTING SYSTEM v Filed Nov. 10, 1932 2 Sheen's-Sheet 1 IN V ENTOR.

, Henry L. Logan.

A TTORNE).

Jan. 8, 1935.

H. LOGAN v DENTAL LIGHTING SYSTEM Filed Nov.. 10, 1932 2 Sheets-Sheet 2INVENTOR. Henry L. Logan.

A TTORNEYI Patented, Jan. 8, 1935 LIGHTING SYSTEM Henry L. Logan, NewRochelle, N. Y., asaignor to Holophane Company, Inc., New York, N. Y., acorporation of Delaware Application November 10, 1932, Serial No.641,969

3 Claims. (Cl. 240-1) than those in common use.

The use of a fixed system of fighting for dental work has heretoforebeen considered impossible as a general proposition. Owing to thevariation in height of dentists, the height" of the working plane abovethe fioor has to be varied, and, owing to the variation in height of thepatient, there is a considerable range in the positions of the mouth,both as to its elevation above the floor and its position relative tothe center or support of the dental chair. It is also desirable to swingthe chair to some extent about this pivot. The net result of theseconditions is that the mouth may be placed in an operating region whichvaries about one foot in height and has a horizontal dimension of a footor more.

The lighting of the mouth during dental operations requires a highintensity of illumination with the light directed onto the surfaces onwhich the dentist is working, so that he can carry out the operationswith adequate lighting, all of which must be received through thecomparatively small opening of the mouth. The dentist .must be close tothe patient and the operations must be carried out in various places inthe mouth by instruments which the dentist holds in his hand, so thatavoiding the creation of shadows in the mouth cavity is, important.These conditions have made it the almost universal practice for thedentist to employ movable light sources comparatively close to thepatient. Such movable lighting apparatus clutters up the space about thepatient and dental chair and requires adjustment by the dentist eachtime he or the patient moves. Such adjustments take the attention of thedentist away from the more important work in hand, are unsanitary, andannoying to th patient.

The present invention contemplates a lighting system for dental usewhich consists essentially of a plurality of simultaneously operatedlight sources placed in fixed positions. They are far above theoperating chair so as not to interfere with the movements of the dentistand require no attention by the dentist. They are constructed toprovide'very intense beams of light projected toward the center of theregion occupied by the mouth cavity. While-the crossing of the beams isat this center, there is a region of considerable depth and width inhorizontal directions which these fixed light sources illuminate to avery high intensity, of the order of 250 foot candles. This is obtainedfrom three such sources with proper lenses and reflectors for projectingthe light toward this theoretical center. The lights are so located asto provide not only horizontal illumination of the mouth cavity, butalso a crossing of the light rays inside the mouth cavity for theillumination of vertical surfaces and to bring about diffusion toilluminateback surfaces. This arrangement also minimizes the casting ofobjectionable shadows by the dentist or the tools which he uses.

The preferred location for these light sources is in or near the ceilingof the room, but where'the room has too high a ceiling, the lightsources can be supported on a chandelier-like structure at the desiredelevation above the operating plane. Once this chandelier is installed,it requires no adjustment so long as the operating center is retained.

In order that the patient will not be unnecessarily annoyed by thelighting, the system is also designed so that the light sources are notwithin the normal field of vision of the patient when in the operatingposition.

Other and further objects and advantages of the invention will beapparent as the description proceeds.

The accompanying drawings show, for purposes of illustrating the presentinvention several'oi the many embodiments in which the invention maytake form, it being understood that the drawings are illustrative of theinvention rather than limiting the same. In these drawings:

Fig. 1 is a diagrammatic view illustrating an angular layout for thelighting units of the system in connection with an operating chair;

Fig. 2 shows a triple spot lighting system viewed from the rear of theoperating chair with the three beams of light directed toward the oper--ating point on the dentist's chair.

Fig. 3 is a cross-section o1 one of the lens units used for this system;

Fig. 4 shows a recessed lighting system with a number of dental chairsand triple spot directed toward each operating point but with lensesgrouped together mechanically wherever possible;

Fig. 5 is an adjustable triple spot lighting unit; and.

Fig. 6 is another form of adjustable triple spot unit. j

Fig. 1 shows the head rest of a dental chair at 10. It is tilted at theusual angle topermit the dentist to work in the mouth (M). The line ,11is projected vertically upward from the mean center of the unit 12,indicate a horizontal plane through the lighting unit 12, the line 13-13 ex tending from the rear oi..the chair toward the front of the whilethe line 14--14 is at right angles to the line 1313.

Two other "lighting units are indicated at 15 and 16. The preferredspacing. of the lighting units 15 and 16 is at theapi'ces'oi anequilateral triangle, the line between the units '15 and 16 beingparallel with the line 14--14 thereby locating these units on oppositesides of the patients mouth. The units 15 and 16 may be alike and aredesigned to project slanting light beams whose axes are indicated at 1'1and 18. These slanting axes intersect the vertical beam axis 11 at apredetermined point which is at the centerof the region in whichoperating work is performed.

The line 19 indicates the normal line of vision iromtheheadrest.Astheheadrestisusually tilted from 30 to 45, this line 01' normal visionvaries from 60? to 45 to the vertical. It has been found by experimentthat the units 15 and- .16 should be placed at such a distance from theunit 12 that the beam axes 17 and 18 are at angles of approximately 35with the vertical asindicatedinthedrawings. Thelineotvisionisthentrom20to30 iromtheaxes otthe beams. With such an arrangement, thelight comes at an angle suiiiciently near the vertical tobeireeiromannoyingglare,exceptwhenthe patient looks up to see the lightingunits, and yet aflords a satisfactory amount of vertical illuminationinside the mouth. It will thus be seenthatthere-arethreebeamsotlight,onevertical mm unit 12, the other two being oblique atangles at35tothevertical and atanglesot about 33 to one another, all directed intothe oral cavity. It will, therefore, be apparent that the light fromthese three sources in the 5 oral'cavity' and is capable of illuminatingvertical and horizontal surfaces and of producing excellent diflusionaround the'mouth for illuminating suriaces which cannot be directlyreached.

This beam arrangement is one in' which the dentist is not annoyed byshadows cast into the mouth by his body or theinstruments he is using.InFig.2the118htingunit lfiisplaceddirectly over the patients mouth inthe dentist chair.

The additional units 15and 16 are placed respectively on each side oi'the central unit and .iorward. Unit 12 has a lens unit directing a beamstraight downward. Units 15 and 16 direct slanting beams atan' angle 'toconverge at the same point, viz., the patients mouth M. The lens units12, 15, audio are'placed on a ceiling, the height of which is indicatedatline C. It the ceiling is higher, as shownby the dotted line C,

' the units are placed farther apart,- but in the same angular relationto one another and so that the beams still converge at exactly the samepoint. Unit 12 is raised to the position 12'. Unit 15 is carried backalong the line 17 to'the position 15'. Unit 16 is carried back along theline 13 to the position 10. By moving these unitsbackalongtheaxesl'iandlsoitheslanting' beams, they are placed at'a newlocation on'the higherceilingsuchthatthebeamsarestilldirected exactly tothe same point as-baioreQIt' directthelightattheproperangledownward. 5

However, a part 01 this angular direction downward is obtained byoii'setting the light center 21 somewhattromthe axisnoithelensmpThispermits a somewhat, lesser degree of tip to the lens than would be nHall of the tip of the light beam were obtained by tipping the lens.When beams or other obstructions on the ceiling interfere with thelocation 01' a unit at exactly the proper point, the unit may be movedto one side or the other. Then the proper angle oibeammaybeobtainedbyachangeinthepofltion of the light center 21 to oneside or the other 01' the position shown in Fig. 3'. In the unit shownin Fig. 3- efliciency is increased by the use of a spherical reflector23 placed above the light source. Diflusing glass sides of opal or Votherglassmaybieusedintheseunitsasindi cated at 24. This gives. a spreador diii'us'ion to the transmitted light as shown at 25 and helps toprovide general illumination in the room with asoitpleasingeflect.

Fig. 4 indicates the application oi the system to an installation havinga plurality or dental chairs. Suchaninstallationmightbeplacedin a dentalcollege. Wherever the proper location'otlensesinsuchasystembringathelensestogether,theyaregroupedtogetherinthesameboxtoobtaintheadvantasesoiabankconstruction of the boxes ior thelamps.

Fig. 5 illustrates, "a triple spot unit as suspended from the ceiling bya single support. A triangular box carriesthree lenses 31, 32, and 33.each with its individual lamp. The lamps are so set with'reierence tothe lens tool as to produce concentration at :the operating 40 point.Inthisunit,thetopcoverottheboxis ward the operating'p'oint. Thedistanoeoi the 1 boxes 36, 37.and 3i! from the adjustment may also beintroduced if desired.

It may sometimes be necessary to have the lighting unit 12 slightlyofiset, so as not to be directly over the center of the operatingregion. Slight inclination of the beam of this unit corrects for thedisplacement of the unit.

The lenses and reflectors are designed to produce beams of very smalldivergence so that the cross section of the beam of controlled light isbut little larger than the lens. A large amount of scattered anduncontrolled light is emitted from each unit so that a high level ofgeneral illumination is available without additional lighting apparatus.

It is obvious that the invention may. be embodied in many forms andconstructions, and I wish it to be understood that the particular formsshown are but a few of the many forms.

for providing intense illumination vertically, and two lighting unitseach having light concentrating lenses. the latter light units beingspaced from one another and equally spaced from the first lighting unitand arranged to'project intense beams of light toward the mouth cavity,the three units having fixed spacial relationship and singularity, saidlighting units being a predetermined distance above the dental chair,the light beams crossing in the region of the mouth cavity toprovideillumination of vertical surfaces such as teeth and gums, the lattermentioned lighting units being placed sufliciently close to the firstunitsoastobebehindthenormaldirectionof sight of the patient to reduceglare from the surface of, the lenses in the patients eyes.

2. Lighting apparatus as set forth in claim 1,

characterized in that the axes of the oblique beams are at substantiallywith the axis of the vertical beam.

3. Lighting apparatus as set forth in claim 1, characterized in that thelighting units are at the apices of an equilateral triangle, theslanting beams being projected at equal angles to the vertical.

HENRY L. LOGAN.

